function zoomToggle(iWideSmall, iHighSmall, iWideLarge, iHighLarge, whichImage)
{
        oW = whichImage.style.width;
        oH = whichImage.style.height;
        if ((oW==iWideLarge)||(oH==iHighLarge))
        {
                nW = iWideSmall;
                nH = iHighSmall;
        }
        else
        {
                nW = iWideLarge;
                nH = iHighLarge;
        }
        whichImage.style.width  = nW;
        whichImage.style.height = nH;
}